Treatment of Wastewater Containing Oil

The possibilities for treatment of a wastewater containing 120 - 170 mg/l of oil, with a COD of 190 - 312 mg O2/l and a pH of 7 - 7.6, were studied. A treatment process consisting of coagulation and adsorption was investigated. The effectiveness of coagulation using aluminium sulphate, ferric chloride, and aluminium chloride, was examined, and for the adsorption process, three activated carbons (A, B, and C) were considered. Carbons A and B were new types of activated carbon based on different pyrolysed brown coals, and carbon C was a commercial activated carbon. It was established that the optimum results were achieved by coagulation with 140 mg/l aluminium chloride (Al2(OH)5Cl), which produced a treated effluent with an oil content of 11 - 12 mg/l, followed by adsorption using activated carbon A, which gave a treated effluent with an oil content below 2 mg/l. Carbon. A could treat up to 2200 bed volumes of water before regeneration of the activated carbon was necessary.